New technique to deliver stem cell therapy may help damaged eyes regain their sight

Engineers at the University of Sheffield have developed a new technique for delivering stem cell therapy to the eye which they hope will help the natural repair of eyes damaged by accident or disease. This could help millions of people across the world retain – or even regain - their sight.

In research published in the journal Acta Biomaterialia, the team describe a new method for producing membranes to help in the grafting of stem cells onto the eye, mimicking structural features of the eye itself. The technology has been designed to treat damage to the cornea, the transparent layer on the front of the eye, which is one of the major causes of blindness in the world.

Using a combination of techniques known as microstereolithography and electrospinning, the researchers are able to make a disc of biodegradable material which can be fixed over the cornea. The disc is loaded with stem cells which then multiply, allowing the body to heal the eye naturally.

“The disc has an outer ring containing pockets into which stem cells taken from the patient’s healthy eye can be placed,” explains EPSRC Fellow, Dr Ílida Ortega Asencio, from Sheffield’s Faculty of Engineering. “The material across the centre of the disc is thinner than the ring, so it will biodegrade more quickly allowing the stem cells to proliferate across the surface of the eye to repair the cornea.”

A key feature of the disc is that it contains niches or pockets to house and protect the stem cells, mirroring niches found around the rim of a healthy cornea. Standard treatments for corneal blindness are corneal transplants or grafting stem cells onto the eye using donor human amniotic membrane as a temporary carrier to deliver these cells to the eye. For some patients, the treatment can fail after a few years as the repaired eyes do not retain these stem cells, which are required to carry out on-going repair of the cornea. Without this constant repair, thick white scar tissue forms across the cornea causing partial or complete sight loss. The researchers have designed the small pockets they have built into the membrane to help cells to group together and act as a useful reservoir of daughter cells so that a healthy population of stem cells can be retained in the eye.

“Laboratory tests have shown that the membranes will support cell growth, so the next stage is to trial this in patients in India, working with our colleagues in the LV Prasad Eye Institute in Hyderabad,” says Professor Sheila MacNeil. “One advantage of our design is that we have made the disc from materials already in use as biodegradable sutures in the eye so we know they won’t cause a problem in the body. This means that, subject to the necessary safety studies and approval from Indian Regulatory Authorities, we should be able to move to early stage clinical trials fairly quickly.”

Treating corneal blindness is a particularly pressing problem in the developing world, where there are high instances of chemical or accidental damage to the eye but complex treatments such as transplants or amniotic membrane grafts are not available to a large part of the population.

The technique has relevance in more developed countries such as the UK and US as well, according to Dr Frederick Claeyssens. “The current treatments for corneal blindness use donor tissue to deliver the cultured cells which means that you need a tissue bank. But not everyone has access to banked tissues and it is impossible to completely eliminate all risks of disease transmission with living human tissue,” he says. “By using a synthetic material, it will eliminate some of the risk to patients and be readily available for all surgeons. We also believe that the overall treatment using these discs will not only be better than current treatments, it will be cheaper as well.”

The research is supported by a Wellcome Trust Affordable Healthcare for India Award to the University of Sheffield and the LV Prasad Eye Institute, where the work is led by Associate Director and Head of Clinical Research, Dr Virender Sangwan. The work has also been supported through a Research Fellowship for Dr Ortega from the Engineering and Physical Sciences Research Council (EPSRC).

Additional information

IMAGES: photo of Dr Ílida Ortega Ascencio with the disc for grafting stem cells to the eye
VIDEO: University of Sheffield film of Dr Ílida Ortega Ascencio explaining how the disc works at: http://www.youtube.com/watch?v=Maw645eENL4

2. The World Health Organisation report – Corneal blindness: a global perspective –states that: ‘Diseases affecting the cornea are a major cause of blindness worldwide, second only to cataract in overall importance … While cataract is responsible for nearly 20 million of the 45 million blind people in the world, the next major cause is trachoma which blinds 4.9 million individuals, mainly as a result of corneal scarring and vascularization.’

3. Dr Ílida Ortega, Dr Pallavi Deshpande, Professor Sheila MacNeil and Dr Frederick Claeyssens are all members of the Biomaterials and Tissue Engineering Group, in the University of Sheffield’s Department of Materials Science and Engineering. Professor Anthony Ryan is in the University of Sheffield’s Department of Chemistry.

4. The Faculty of Engineering at the University of Sheffield - the 2011 Times Higher Education’s University of the Year - is one of the largest in the UK. Its seven departments include over 4,000 students and 900 staff and have research-related income worth more than £50M per annum from government, industry and charity sources. The 2008 Research Assessment Exercise (RAE) confirmed that two thirds of the research carried out was either Internationally Excellent or Internationally Leading.

The Faculty of Engineering has a long tradition of working with industry including Rolls-Royce, Network Rail and Siemens. Its industrial successes are exemplified by the award-winning Advanced Manufacturing Research Centre (AMRC) and the new £25 million Nuclear Advanced Manufacturing Research Centre (NAMRC).

The Faculty of Engineering is set to ensure students continue to benefit from world-class labs and teaching space through the provision of the University's new Engineering Graduate School. This brand new building, which will become the centre of the faculty´s postgraduate research and postgraduate teaching activities, will be sited on the corner of Broad Lane and Newcastle Street. It will form the first stage in a 15 year plan to improve and extend the existing estate in a bid to provide students with the best possible facilities while improving their student experience.

5. The Wellcome Trust is a global charitable foundation dedicated to achieving extraordinary improvements in human and animal health. It supports the brightest minds in biomedical research and the medical humanities. The Trust’s breadth of support includes public engagement, education and the application of research to improve health. It is independent of both political and commercial interests.www.wellcome.ac.uk

6. The Engineering and Physical Sciences Research Council (EPSRC) is the UK’s main agency for funding research in engineering and physical sciences. EPSRC invests around £800m a year in research and postgraduate training, to help the nation handle the next generation of technological change.
The areas covered range from information technology to structural engineering, and mathematics to materials science. This research forms the basis for future economic development in the UK and improvements for everyone’s health, lifestyle and culture. EPSRC works alongside other Research Councils with responsibility for other areas of research. The Research Councils work collectively on issues of common concern via research Councils UK.